Anatomical Head and Neck Restraining Sleep Aid and Related Products and Methods

ABSTRACT

The invention provides head and neck support sleep aid devices and methods for securely restraining the head of fatigued and sleeping travelers seated in a constrained, upright position, to prevent involuntary forward or lateral head flexion. The devices and methods of the invention employ a rigid elongate lever member adapted to be interposed between a user&#39;s back and an upright seat surface and head bracing means connected to the lever member to restrain the user&#39;s head against forward and lateral flexion.

TECHNICAL FIELD

The invention relates to products and methods for stabilizing the head and neck of a human subject to maintain the head in a static upright position at rest. More specifically, the invention relates to sleep aids for firmly but comfortably restraining the head and neck of a seated subject in a relaxed upright position to facilitate sleep, for example during extended commercial travel.

BACKGROUND OF THE INVENTION

Travelers and commuters are forced to sit in a confined upright position for long periods, making it difficult to rest or sleep. Thus restrained, sleep is typically prevented or compromised due to the passenger's inability to relax the musculature of the neck and head. Anyone who has tried to sleep on an airplane, bus or train understands this problem, where at the point of falling asleep the neck musculature relaxes and the head flops forward or lolls sideways. This results in an abortive sleep experience that is fitful, uncomfortable, unrestful, and in some cases even injurious, with the additional drawback that involuntary head movements can encroach on the personal space and comfort of neighboring passengers.

While awake humans subconsciously employ their neck muscles to hold their head in a normal upright orientation. These muscles are complex and can also function voluntarily to sweep the head sideways (lateral panning), crane the head forward (ventral flexion) or backward (dorsal flexion), or tilt the head sideways (lateral flexion). When we fall asleep or become fatigued, the muscles of the neck relax. For an individual seated upright, this can allow the head to inadvertently fall forward or sideways, causing discomfort and disrupting restful sleep. This is because the head is not balanced in an upright position, rather the load center of gravity of the head is forward of a pivot point or center of head flexion in the cervical portion of the spine. Off-vertical axial separation between the head's center of gravity and the center of head flexion dictates an imbalance of forces caused by gravity, which operate to pitch the head forward (ventrally) when the active restraint of neck flexor muscles (holding the head in an upright position by pulling the base of the skull backward, or dorsally) is absent. Thus, when the neck muscles are relaxed or “off duty”, as during sleep, the head of an upright seated individual will typically fall forward and/or loll sideways. The individual may react unconsciously by jerking the head back erect, which can cause discomfort or embarrassment and may even result in injury for individuals with orthopedic complications. If sleep continues with the head ventrally and/or laterally flexed without support, this too can result in prolonged discomfort, breathing impairment or injury.

Various devices have been proposed to restrain the head of an upright seated traveler in a comfortable position to facilitate sleep. Dozens of “travel pillow” devices have been designed and marketed for this purpose, generally sold as “head and neck support sleep aids” for commuters and commercial passengers. Most of these are horseshoe-shaped cushions worn around the neck as a collar, with a cylindrical or square cross-section foam core. These devices provide only limited restraint against involuntary, lateral head flexion, and essentially no restraint against ventral head flexion. Other collar restraint designs provide adjustable, higher-profile and more compression-resistant rear and side restraint designs, for example by affording adjustable thickness/height inserts (see, e.g., U.S. patent Ser. No. 10/051,967). One particularly complex collar design employs stiffening inserts to improve lateral compression resistance, as well as drawstrings to cinch the collar more firmly against the wearer's neck to afford greater support and compression resistance against rear and lateral head flexion (see, e.g., U.S. Pat. No. 9,635,962).

A common deficiency of collar-style head and neck supports is their open collar design, which provides no frontal section to resist forward head flexion. Indeed, collar designs generally preclude a frontal support structure, because the wearer's mandible would tend to compress that segment of the collar against the user's trachea resulting in airway restriction during sleep.

One alternative traveler's sleep aid described in U.S. patent Ser. No. 10/178,915 purports to address the problem of forward head flexion by providing a support collar with “anchoring straps” to “prevent or make less likely a user's head falling forward”. This device also features a horseshoe collar but with rear anchoring straps for attaching the collar to a seat or headrest to anchor the device against forward movement. The strap design is complicated and intrusive to deploy, and is suited to a limited range of seat types. Yet the key drawback to this device is, again, that its frontal opening provides little or no resistance to downward gravitational forces that drive downward-forward head flexion during sleep.

A different type of head support device is described in U.S. Pat. No. 7,004,545 issued in 2006 to Miller. The Miller device employs a substantially flexible, planar support member sandwiched between a user's back and a seat surface. A securing member attaches to the support member and encircles the user's head, securing the user's head relative to the support member. According to Miller, this design maintains the head of a user in a stable, upright position during sleep. For reasons that will become apparent from the description which follows, the support device of Miller presents fundamental deficiencies in design, operation, ease of use, comfort, and performance, evidently meeting with practical and commercial failure precedent to abandonment of Miller's '545 patent long before its expiration.

In view of the foregoing, there is a long unmet need in the art for head and neck support devices for commuters and travelers that adequately restrain forward and lateral head flexion during sleep when the user is constrained to an upright, seated position. A related need exists for traveler's sleep aid devices and methods that effectively restrain the head against forward and lateral flexion while imposing minimal orthopedic stress on the user's head, neck and back to provide optimal comfort over long periods of use.

SUMMARY OF EXEMPLARY EMBODIMENTS OF THE INVENTION

The invention fulfills the foregoing needs and satisfies additional objects and advantages by providing a novel sleep aid head and neck restraint device for travelers and commuters, the device featuring an orthotic lever support and connecting head brace element that operate to restrain the user's head firmly but gently in a comfortable, upright equilibrium position against frontal and lateral flexion forces caused by gravity, turbulence, changes in vehicular direction, and vehicular deceleration.

The travel sleep aid device of the invention comprises a rigid elongate lever member sized and contoured to fit comfortably between a thoracic spinal region of the user's back and an upright seatback surface, and head-bracing means attached to the upper lever arm to positionally secure the user's head relative to the upper lever arm.

In certain embodiments a middle or mid-lower section of the lever member is bent or curved, at least on a frontal face, proscribing a frontal angular or arcuate anatomical load displacement bend between the upper and lower lever arms.

In exemplary embodiments the head bracing means includes a comfortable, textile strap, brace harness or other restraint element that grips or encircles the user's head, to securely engage and restrain the head against frontal and lateral flexion. In alternate embodiments, the head brace means can be tightened or loosened to fit the head sizes of different users, or increase or decrease force of engagement of the user's head, and/or adjusted vertically to position the head brace means in height to fit users of different sizes.

In certain embodiments, the travel sleep aid device of the invention is further orthotically modified to optimally distribute thoracic load, by providing a front surface of the lower lever arm, and optionally other portions of the device, that is/are transversely concave, defining a thoracic load distributing transverse arc having a radius of curvature of from 10 inches to 40 inches over at least a portion of the lower lever arm.

In alternate embodiments the travel sleep aid device of the invention may incorporate one or more stiffening members to afford increased rigidity in at least a longitudinal flexion axis, for example longitudinal stiffening rods, inserts, ribs, channels or other stiffening elements incorporated within a body of the lever member or structurally joined to the front or back of the lever member, providing longitudinal stiffening to prevent frontal deformation (bending or flexion) of the lever member to increase resistance against frontal head flexion. In exemplary embodiments the lever member incorporates longitudinal stiffening ribs extending from at least a portion of the back surface of the lever member.

In distinct aspects of the invention, a novel stiffening design is employed for the elongate lever member that optimizes anatomical load distribution and resistance, while at the same time affording novel benefits for commercial handling of the device. In one exemplary embodiment, the rigid elongate lever member incorporates longitudinal stiffening ribs extending rearward from right and left sides of the back surface of the lever member, wherein the stiffening ribs are highest at a middle region of the rigid elongate lever member and diminish in height from the middle region toward top and bottom edges of the lever member. At their highest points, corresponding to a functional mid-section of the lever member, the stiffening ribs extend from the back surface at an obtuse angle (i.e., rearward and laterally) relative to a horizontal stacking axis of the lever member. This novel construction provides for compact stacking of multiple lever members for efficient storage and shipping without unacceptable loss of rigidity provided by the stiffening ribs.

In other discrete aspects of the invention, novel methods for restraining the head of a fatigued or sleeping person seated in an upright position are provided, which effectively minimize involuntary forward and lateral flexion of the head. According to exemplary methods herein, the user positions a rigid elongate lever member between a thoracic spinal region of their back and an upright seatback surface, the lever member having front and back surfaces and comprising upper and lower lever arms, wherein a width dimension of the upper lever arm is less than a width dimension of the lower lever arm,

and a midsection of the lever member defines an angular or arcuate longitudinal anatomical load displacement bend of the frontal surface between the upper and lower lever arms. The user adjusts vertically and selects an anchored position of the lower lever arm and load displacement bend to locate an operative “fulcrum” of the rigid elongate lever member that yields optimum, comfortable force balancing, by positioning the load displacement bend between the seat surface and a mid-thoracic portion of his or her back, with the lower lever arm positioned between the seat surface and a mid-lower-thoracic portion of the back. Head-bracing means are attached to secure the head to the upper lever arm, whereby frontal flexion loads of the user's head when neck muscles are relaxed during fatigue or sleep are opposed by rearward forces operating on the upper lever arm from the lower lever arm and fulcrum, transmitted through the head-bracing means.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a left side orthographic view of a seated traveler with a device of the invention deployed.

FIGS. 1B and 1C illustrate loading force distribution (arrows) and zonal fulcrum (shaded areas) during operation on a rigid elongate lever member of the invention (at equilibrium FIG. 1B; under frontal head flexion loading FIG. 1C.

FIG. 2A provides a left rear pictorial view of a device of the invention featuring novel longitudinal support means and height adjustable head brace means.

FIG. 2B provides a right rear pictorial view of a device of the invention with height adjustable head bracing means securely engaging an average-sized adult user's head.

FIG. 2C provides a right rear pictorial view of a device of the invention with height adjustable brace means adjusted to an upper-most selectable position and securely engaging a larger than average-sized adult user's head.

FIG. 3A provides a rear orthographic view of an exemplary rigid elongate lever member of the invention.

FIG. 3B provides a right-side orthographic view of an exemplary rigid elongate member design of the invention.

FIG. 3C provides a longitudinal axis sectional view along A-A of FIG. 3A (corresponding to longitudinal midline) of an exemplary rigid elongate lever member design of the invention showing upper and lower lever arms (and frontal longitudinal axes of upper and lower lever arms), and curvature of a novel anatomical load displacing bend of the lever arm.

FIG. 3D provides a lateral sectional view along B-B of FIG. 3A corresponding to a bottom region of a rigid elongate lever member of the invention illustrating a thoracic load distributing transverse arc.

FIG. 3E provides a lateral sectional view along C-C of FIG. 3A corresponding to the mid height region of a lever member of the invention showing a thoracic load distributing transverse arc.

FIG. 3F provides a lateral section view along D-D of FIG. 3A corresponding to the top region of a design of a lever member of the invention featuring little or no transverse curvature.

FIG. 4A provides a right rear pictorial view of a device of the invention depicting exemplary, height-adjustable head bracing means engaged to positionally stabilize a user's head.

FIG. 4B provides a right rear pictorial view of a device of the invention depicting exemplary, height-adjustable head bracing means engaged to positionally stabilize a user's head.

FIG. 4C provides a right rear pictorial view of a device of the invention illustrating alternative height-adjustable head bracing means.

FIG. 4D provides a right rear pictorial view of a device of the invention illustrating alternative height-adjustable head bracing means.

FIG. 4E provides a right rear pictorial view of a device of the invention illustrating alternative height-adjustable head bracing means.

FIG. 5 provides a rear orthographic view of a rigid elongate lever member of the invention selectably positioned for desired force distribution, zonal fulcrum placement, and comfort relative a user's cranial and thoracic skeletal anatomy.

FIG. 6A provides a rear pictorial view of two rigid elongate lever members of the invention stably nested one atop the other, illustrating novel, compact and stable stacking features of the invention.

FIG. 6B provides a rear orthographic view of a rigid elongate lever member of the invention featuring a novel longitudinal support member design enhancing device rigidity and yielding compact and stable stacking advantages.

FIG. 6C provides a lateral sectional view along B-B of FIG. 6A depicting novel stacking features of nested, rigid elongate lever members of the invention.

FIG. 6D is a close-up partial view taken from FIG. 6C, depicting novel stacking stability features of nested, rigid elongate lever members of the invention.

FIG. 6E provides a lateral sectional view along A-A of FIG. 6A depicting novel stacking features of nested, rigid elongate lever members of the invention.

FIG. 6F provides a close-up partial view taken from FIG. 6E, depicting novel spacing features of nested, rigid elongate lever members of the invention correlated with increased stacking stability.

FIG. 7A provides a left rear pictorial view showing a contour grid depicting multi-axis curvature of a back surface of a rigid elongate member of the invention.

FIG. 7B provides a right front pictorial view showing a contour grid depicting multi-axis curvature of a front surface of a rigid elongate member of the invention.

A DETAILED DESCRIPTION OF THE INVENTION

Turning now to illustrate more detailed embodiments of the invention, the novel travel sleep aid device 10 provided here functions as a Class I lever, integrating a rigid elongate lever member 12 anchored between a user's back 14 and an upright seat back 16 to delicately balance and resist frontal and lateral flexion loads of the user's head 18 (FIG. 1A). The user's head is comfortably held stationary relative to an upper lever arm 20 of the lever member 12 by anatomically conforming head bracing means 22, for example a clamping, cradling, harnessing or strapping element. In use, a lower lever arm 24 of the lever member receives effort and fulcrum forces from the user's back and seat back, which collectively, reflexively oppose frontal and lateral flexion loads generated by the user's head when the user's neck muscles are relaxed or fatigued and gravity compels the head to fall forward (flex frontally or ventrally) or sideways (flex laterally in either direction).

The rigid elongate lever member 12 is typically substantially planar over at least one or more portion(s) of its structure, including most or all of the upper lever arm 20 and also the lower lever arm 24, although the latter may in some embodiments be transversely curved for additional advantages as described below.

As noted, the rigid elongate lever member 12 is sized and dimensioned to fit comfortably between a mid-thoracic spinal region (defined as an approximate region spanning the fourth thoracic vertebra, “T-4” in FIG. 1 , to the 10^(th) thoracic vertebra, “T-10” in FIG. 1A) of an average sized user's back 14 and an upright seatback 16 surface when the user is seated upright. The lever member functions by providing upper and lower “lever arms”, 20 and 24, respectively, which may be identified structurally, or merely operationally. In exemplary embodiments, as depicted in FIGS. 1A and 2A, the lever arms are separated by a distinct structural transition, such as an anatomical load displacing bend 26 in the lever member, while in other embodiments the lever arms are defined functionally. With regard to the latter definition, the upper lever arm is defined as a portion of the lever member extending above an operative fulcrum point or zone (see below), and the lower lever arm is defined as a portion of the lever member extending below the operative fulcrum point or zone (generally including a lower segment of the lever member immovably pinned between the user's back and seat surface).

The front and back profiles of the rigid elongate lever member 12 may be cost-effectively provided in a simple form, for example a rectangular form (i.e., with similar top and bottom, and opposing side, widths and lengths, respectively—in other words having flat, parallel and equal dimensioned top and bottom edges, and opposing side edges). More commonly, an upper width 30 of the lever member at a topmost point 32 (i.e., a top edge of the upper lever member) will be substantially less than a width of the lower lever arm, which may be relative to an entire length of the lower lever arm, or minimum as compared to a lower width 36 at a bottom edge 38 of the lower lever arm 24 (see, e.g., FIG. 3A). In exemplary embodiments, as illustrated in FIG. 3A, the rigid elongate lever member 12 is tapered from a widest point at the bottom 38 of the lower lever arm 24 to a narrowest point at the top 32 of the upper lever arm 20 to provide a generally triangular, trapezoidal or spatulate frontal profile of the lever member 12 as a whole.

As noted, the travel sleep aid device 10 of the invention comprises a rigid elongate lever member 12 sized and contoured to fit comfortably between an approximate mid-thoracic spinal region 124 (spanning from T-4 to T-10 as depicted in FIG. 1A) of an average sized adult user's back 14 and an upright seatback 16 surface, connected to head-bracing means 22 permanently or removably, and optionally adjustably, fixed to the upper lever arm 20, positionally securing the user's head 18 relative to the upper lever arm (see, e.g., FIG. 1A, and FIG. 5 ). Frontal flexion loads generated by the user's head against the head bracing means are opposed by rearward work forces transmitted through the bracing means by the upper lever arm, which is in turn biased by forward effort forces applied against a back or rear surface 40 of the lower lever arm 24 by the seat back 16, while the lower lever arm is forcibly pinned against its front surface 44 by the user's back, creating a “fulcrum”. Because of the shifting and transient nature of loading on the lever member, and the often zonal nature of loading and balancing forces generated by different embodiments of the invention, the fulcrum itself is generally not a set pivot point as in conventional terms, but is best comprehended as a zonal, shifting, transient fulcrum reflexive to multiple loading factors (see below).

In certain embodiments the rigid elongate lever member 12 is anatomically modified to be frontally curved (bent forward or concave along a frontal surface 46) at a middle or mid-lower curved section 48 of the lever member (see FIG. 3B). Within these embodiments the frontal face 46 of the lever member proscribes a frontal, angular or arcuate, longitudinal anatomical load displacement bend 50 between the upper and lower lever arms (see FIGS. 3A, 3C). As illustrated in FIG. 1A, this novel orthotic design functions to delicately balance lever and fulcrum forces of the device 10 to maintain the user's head 18 more comfortably restrained and balanced against frontal and lateral flexion forces during sleep, fatigue, and ordinary head displacement forces, for example as resulting from jostling or turbulence attending air, bus, train or other vehicular travel.

In more detailed embodiments, the longitudinal anatomical load displacement bend 26 comprises at least a five-degree angle or curve of the frontal surface 48 between the upper lever arm 20 and lower lever arm 24, whereby a frontal longitudinal axis of the upper lever arm 50 diverges frontally at least five degrees from a frontal longitudinal axis of the lower lever arm 52 (see FIGS. 3C and 7B). In other embodiments the longitudinal anatomical load displacement bend comprises an angle or curve of the inner surface no greater than 30 degrees between an upper end or top edge 32 of the upper lever arm and a lower end of the lower lever arm (bottom edge 38), whereby the frontal longitudinal axis of the upper lever arm 50 diverges frontally no more than 30 degrees from the frontal longitudinal axis of the lower lever arm 52. In additional embodiments the longitudinal anatomical load displacement bend comprises an angle or curve of the inner surface within a range of 10-20 degrees between an upper end of the upper lever arm and a lower end of the lower lever arm, whereby a frontal longitudinal axis of the upper lever arm diverges frontally within a range of 10-20 degrees from a frontal longitudinal axis of the lower lever arm. In one illustrative working example, the longitudinal anatomical load displacement bend comprises an angle or curve of the inner surface selected from within a range of 14-18 degrees between the upper end of the upper lever arm and lower end of the lower lever arm, whereby a frontal longitudinal axis of the upper lever arm diverges frontally within a range of 14-18 degrees, or about 16 degrees, from the frontal longitudinal axis of the lower lever arm. An exemplary embodiment wherein an angle of curvature 56 of the longitudinal anatomical load displacement bend 26 fits an exemplary range of between about 14-18 degrees is depicted in FIG. 3C.

According to these aspects of the invention, the upper and lower lever arms, 20 and 24, are defined as the upper and lower portions of the rigid elongate lever member 12 separated by the anatomical load displacement bend (generally depicted in FIGS. 3B and 3C as the curve 26 defining a middle or mid-lower curved section 48 of the lever member). This bend may be a sharp angle, crease or bend, and thus may be disposed over a short longitudinal segment of the lever arm, for example about 0-0.5 inches. Alternatively, the longitudinal anatomical load displacement bend may be a moderately tight crease or bend disposed over a distance of between about 0.25-0.75 inches separating the upper and lower lever arms (i.e., defining a moderately tight-curved frontal surface bend between the upper and lower lever arms). In other embodiments the anatomical load displacement bend may be a relaxed arcuate bend disposed over a distance of between about 0.75-4.0 inches between the upper and lower lever arms, defining a shallow-arc curved frontal surface bend between the upper and lower lever arms.

The foregoing novel aspects of Applicant's device 10 uniquely anatomically optimize functionality of the rigid elongate lever member 12 for maintaining a user's head 18 position at an effortless equilibrium rest position, keeping the head upright with little or no activity of the neck muscles (i.e., during sleep or fatigue) when the user is resting in an upright seated position. In general terms, an upright seated position, for example in a commercial airliner, bus, train or auto, is determined by the seat's ability and range of tilt from a practical minimum of 0 degrees (vertical). Most travel seatback cushions have some degree of tilt angle inclining off-vertical toward a dorsal (rearward) direction for comfort. Additionally, many travel seats are contoured, whereby the tilt angle may vary as a function of height (for example, the head rest on many aircraft seats protrudes substantially in the ventral (frontal) direction. For general definition purposes, the following examples provide reference tilt angles for seatbacks measured at an illustrative height corresponding to a mid-upper thoracic portion of a user's back (e.g., at about a level corresponding to vertebra T-7 of an average user). Seated against a vertical wall the reference tilt angle as noted will be an extreme minimum of 0 degrees. A standard commuter bus seat provides an upright seating rearward tilt angle of about 10 degrees. An equilibrium seating angle, where the seated passenger's head is closely approximating equilibrium balance between ventral and dorsal flexion forces, was determined herein to be about 23 degrees. Beyond 30 degrees dorsal-directed forces are determinative and the passenger's head is driven back by gravity to make forcible contact with the seatback. Accordingly, as defined herein, an “upright” seated position generally describes all seat tilt configurations, as generally afforded in commercial transit environments, corresponding to less than about 25 degrees, and in some cases less than about 30 degrees, dorsal or rearward tilt. This broad range of applications is suitable here, because the invention is suited to restrain forward head flexion during such circumstances as air turbulence or bad road or rail conditions, when the head can be jogged to flex ventrally even when the user is seated “upright” with a dorsal or rearward tilt angle of between 23 degrees and 30 degrees (i.e., between an equilibrium position and a substantially rear- or dosal-biased tilt position). It is additionally contemplated that the device of the invention will serve substantial benefits even when the user is not seated upright, but is resting in a “reclined” position (e.g., in a seat tilted back between about 26-30 degrees, or greater than 30 degrees dorsal or rearward). In these circumstances, even when the risk of forward head flexion is minimal or absent, the invention continues to provide restraint against involuntary lateral head flexion and panning movements that can disturb sleep and impose on the space of adjacent travelers.

In related embodiments the remainder of the rigid elongate lever member 12, apart from the longitudinal anatomical load displacement bend 26 (and corresponding middle or mid-lower curved section 48 of the lever member), when present may be substantially straight or planar. Thus, in certain embodiments the frontal surfaces of the upper and lower lever arms (above and below the angled or curved bend when present) are substantially straight, at least along their mid-frontal, longitudinal axes (corresponding to lines 50 and 52 in FIG. 3C—i.e., they may be generally straight in the longitudinal midline, from the bend to their respective top 32 and bottom 38 edges). In related embodiments, the frontal surface of the upper lever arm 20 may be substantially planar (i.e., with little or no longitudinal or transverse curvature or other deformation), and generally smooth (i.e., without holes, ridges, open cells, bumps, creases or other surface elaborations). The lower lever arm 24 may also be smooth on the frontal surface and substantially straight longitudinally (along the sides as well as the longitudinal midline). In more detailed embodiments, while the upper lever arm may be substantially planar, at least at an upper terminal portion 60 of the upper arm (see FIG. 2A), the lower arm 24 may be desirably transversely curved (bent in the horizontal axis), as described in detail below.

A diverse array of head bracing means 22 can be selected and adapted for use within the devices and methods of the invention, for example selected from comfortable, anatomically conforming, pliable textile straps, braces, harnesses, and cranial-conforming padded clamps, braces, cradles or molded shells, among other devices. As illustrated in FIG. 1A, these head restraint elements are connected to the upper lever arm 20 and operate to grip, traction or encircle the user's head 18 to securely engage and restrain the head against frontal and lateral flexion. In certain embodiments the head bracing means can be adjusted, shortened, lengthened, repositioned, substituted or otherwise adapted or modified to adjust a fit of the head brace means 22 for different sized users, different seating angles, different user postures, and even different anatomical characteristics (e.g., forehead slope) of users. In other embodiments the head brace means can be shortened or lengthened or otherwise tensioned, loosened or adjusted to alter a head-engaging dimension or placement of the brace means, and/or to increase or decrease friction or other engagement/restraint force applied by the brace means to the user's head (for example to accommodate higher flexion loads for heavier individuals or during periods of turbulence).

In certain embodiments, as depicted in FIGS. 2A-2C, the head bracing means comprises a flexible (bendable) textile strap 22′ or harness permanently or removably attached to the upper lever arm sized and configured to surround the user's head and comfortably secure and restrain the user's head in close proximity to the functionally fixed location of the upper lever arm 60. For example, a flexible textile strap or closure 22″ can be used that surrounds the user's head in secure contact with at least a frontal portion 64 of the user's head (e.g., against the forehead, typically above the brow 66) to tether the head to a brace-anchoring segment of the upper lever arm 20. The brace anchoring segment is structurally and operationally defined as a portion of the upper lever arm bearing attachment means for securing the head brace means thereto. As depicted in FIG. 2A the brace anchoring segment corresponds to the entire upper terminal portion 60, which is spanned by attachment means (described below). In illustrative embodiments the head-bracing means comprises a flexible, elastic strap 22′, which may be in the form of a simple loop sized and dimensioned to elastically fit over and firmly embrace the user's head, permanently or removably affixed to the upper lever arm.

In more detailed embodiments, the head bracing means 22 comprises a flexible, optionally elastic or semi-elastic, textile strap 22′ or closure 22″ attached to an upper, brace-anchoring segment of the upper lever arm 20 and extending therefrom, sized and dimensioned to surround the user's head 18 in secure contact with at least the frontal portion 64 of the user's head. In exemplary embodiments, the strap or closure is sized and dimensioned to fit comfortably seat against and securely engage the user's forehead, passing above (or over) the ears and seating just above the brow, for which design the strap or closure optimally has a strap or closure width 68 of between about 1-4 inches, often between about 1.5-3.0 inches, or within a range of from 2.0 to 2.5 inches. The strap or closure can be constructed from any flexible inert (biologically compatible) textile material, for example a woven, knitted or braided natural or synthetic fiber material. In certain embodiments the strap or closure is formed at least in part from cotton, wool, leather, hemp, bamboo or any other suitable, natural textile or fiber material. In other embodiments the strap or closure is made at least in part of nylon, polyester, polypropylene or another synthetic textile or fiber material.

In more detailed embodiments, the head bracing means comprise a head engaging strap 22′, closure 22″ or harness that is not only flexible for bending and conforming to a user's head, but also elastic to improve fit and comfort. The skilled artisan will appreciate that a wide range of materials can be selected and tested, having a wide range of elasticity, to determine optimal elastic or semi-elastic strap, closure and harness materials for use within the devices and methods of the invention. In certain embodiments, the travel sleep aid device employs a flexible, elastic or semi-elastic strap or closure formed at least in part of latex, natural rubber or neoprene (polychloroprene). In exemplary embodiments, the strap or closure comprises a latex, natural rubber or neoprene layer covered on at least one surface with a bonded textile layer, for example a nylon cloth layer, for improved comfort and breathability. Thus, different head bracing means may be constructed of flexible, semi-elastic nylon 1 neoprene or nylon 2 neoprene covered on one or both sides of the strap or closure with nylon fabric bonded to the neoprene for enhanced comfort, semi-elastic performance, and improved breathability. As used herein, “semi-elastic” equates with functional properties, for example a degree of elasticity that provides adequate stretch ability to pull a head bracing strap over a user's forehead, and/or allow modest head movements within a seated strap or closure, while still affording sufficient friction of head engagement to ensure forcible restraint of the head against excessive lateral or frontal flexion. In more detailed embodiments, a flexible, semi-elastic strap 22′ or closure 22″ is provided having at least a portion of an inner surface of the strap or closure adapted for more securely contacting and engaging a user's forehead, generally above the brow 66, comprising open celled neoprene for improved breathability and enhanced friction to securely engage and restrain the forehead, particularly for users with an above average slope to the forehead (i.e., having a forehead that is less vertical than average, wherein the strap or closure tends to slide off the forehead toward the top of the head). For this anatomical feature as well, the strap or closure width 68 and/or height may also be widened and/or lowered, to increase the area of contact and optionally lower the strap or closure further down, e.g., to extend and seat more securely partly below the brow, or primarily below the brow to cover the eyes (in the latter design the bracing strap or closure may optionally have circum-orbital padding to keep the strap or closure from imposing pressure on the eyes). In alternate embodiments, when the strap or closure seats above the brow, the head brace means may additionally include or support eye-covering elements, for example fixed or detachable eye covering mask or patch(es), to enhance user comfort for privacy and sleep. In one exemplary embodiment, a front portion of the strap or closure has hook and loop material to which an eye mask or patch(es) equipped with complementary hook and loop material can be readily attached and detached to cover and uncover the user's eyes as desired.

In other detailed embodiments of the invention the head-bracing means 22 may comprise an adjustable-length strap 22′ or closure 22″ that can optionally be shortened and lengthened, or otherwise tensioned or loosened, to accommodate different sized user's heads, and/or to increase or decrease friction forces mediating secure contact of the strap or closure with the user's head. In the illustrative example of a flexible strap, strap-length adjustment means may be integral to a strap assembly or mounted to or integrated within the upper lever arm. In one example, the strap length adjustment means comprises a cam buckle or tri-glide slide anchored to one end of a strap assembly, the buckle or slide adapted to adjustably receive and secure a free strap end to mediate secure shortening and lengthening of the strap to adjust fit and tension of the strap relative to the user's head.

In other aspects of the invention, the head-bracing means comprise an adjustable closure 22″, for example having left and right closure strap ends 70 and 72, respectively, each anchored (separately, or as one contiguous strap element) to the upper lever arm 20, with the strap ends each sized and dimensioned to surround part of the user's head and to meet or overlap alongside or in front of the user's head (see, FIG. 2A). In these embodiments the closure is combined with adjustable coupling means to secure opposing strap ends together to form a secure closure. In more detailed embodiments, the closure strap ends can be overlapped a greater or lesser distance of overlap prior to securing the coupling means, whereby the closure is length-adjustable as selected by the user to accommodate different head sizes or tensioning preferences or needs. Thus, for example, one head bracing means of the invention employs left and right strap ends having terminal strap segments of mating hook material 74 and loop material 76 on opposing faces that interlock securely when the strap ends 70, 72 are overlapped. For adjustability, the left and right strap ends may be provided with terminal hook and loop segments sized and dimensioned to afford a range of closed strap circumferences to accommodate different head sizes and strap tensions.

Yet another aspect of the invention relates to novel features for anchoring the head bracing means 22 to the upper lever arm 20. In certain embodiments, the head bracing means comprises a flexible textile strap 22′ or closure 22″ anchored to the upper lever arm at one or more side or rear brace anchor point(s). Depending on the anchoring design, the brace anchor point(s) may be distributed over a portion of the upper lever arm substantially coincident with the upper terminal portion 60 identified in FIG. 2A, or may be more focal. In general terms, attached either to the back surface or sides of the upper lever arm, the strap or closure includes left and right anchoring segments (78, 80, respectively) secured or tensioned against left and right sides (82, 84, respectively) of the upper lever arm, affording improved comfort and positional stability (see, FIGS. 2A, 2B). This design affords considerable benefits over alternate designs, for example as compared to the option of head bracing means tethered centrally to the front the upper lever arm. The latter design provides inferior head restraint, particularly to oppose lateral head panning and flexion movements.

With regard to restraining lateral head flexion, and additionally for restraining side to side head “panning” movements, yet another novel feature of the invention affording unexpected advantages relates to dimensioning and configuration of the head brace means relative to the upper lever arm 20. While for resisting forward (ventral) head flexion, a width of the upper lever arm where the head brace means attach can be with a broad range of from about 1-6 inches, a width of the upper lever arm 30 (at the upper lever arm top 32, or at a head brace-anchoring point or segment of the upper lever arm) within a range of from about 2-5 inches affords improved separation of the left and right anchoring segments 78, 80 of the strap or closure (when the strap or closure is anchored to side or rear points on the upper lever arm). In other embodiments the width of the upper lever arm 30 at the upper lever arm top 32 or brace-anchoring point or segment is from about 3-4 inches, or from about 3.5-4.5 inches, affording optimal separation of left and right head brace anchoring segments. This dimensioning is discovered here to provide for improved restraint of lateral head flexion and lateral head panning, without sacrificing comfort and while permitting modest, voluntary or user-directed lateral flexion and panning movements. As used herein, a brace-anchoring point is defined as a midpoint, longitudinally, of any one or more fixed or selectable strap attachment sites, for example at mid-strap 22′ or closure 22″ width of the embodiments depicted in FIGS. 2A-2C. Similarly, the term “brace-anchoring segment” of the upper lever arm refers to a longitudinal segment of the upper lever arm over which is/are distributed one or more strap or closure attachment sites or devices (see below). For the embodiments illustrated in FIGS. 2A-2C, wherein the strap attachment is achieved by incorporation of an elongate hook and loop interface disposed on the rear face of the upper lever arm, the brace-anchoring segment is coincident with the extent of the hook and loop interface, and spans and defines the entire upper terminal portion 60 of the upper lever arm (see FIG. 2A).

Yet additional aspects of the invention relate to design and implementation of novel head brace height adjustment features and methods. In illustrative embodiments depicted in FIGS. 4A-4E, the head bracing means 22 is user adjustable by adjusting a height of head brace attachment to the upper lever arm, for example to accommodate a range of user sizes. Head brace height adjustment may be achieved by repositioning the head bracing means to different brace anchor points distributed along a longitudinally-disposed, adjustable brace anchoring segment of the upper lever arm, as defined above. This can provide for alternate, user selectable brace anchor points over a height adjustability range of, for example, between 1-7 inches along the longitudinal axis of a top portion of the upper lever arm. In alternate embodiments, user selectable brace anchor points 90 are provided over a height adjustability range of between 2-6 inches along the longitudinal axis of the upper lever arm, and in certain embodiments over a height adjustability range of between 3-5 inches. Where a smaller height range is suitable (for example in devices scaled for child users) a lesser range of height adjustability, for example, 4-6 inches, 3.5-4.5 inches, or less, is acceptable. In related aspects, the head brace height adjustment means can operate by detachment and reattachment of the head bracing means 22 to different brace anchor points 90 disposed at different longitudinal heights along the upper terminal portion 60 of the upper lever arm 20. (see FIGS. 4C-4E). Alternatively, head brace height adjustment may be achieved by positional re-adjustment of the head bracing means along the longitudinal axis of the upper lever arm without detaching the head bracing means from the upper lever arm.

In certain embodiments, the head brace height adjustment means comprises an elongate, adjustable anchoring interface of hook and loop material affixed to the rear surface 42′ of the upper lever arm, and a segment of mating hook and loop material affixed to a frontal surface of an opposing attachment interface 94 of the head bracing means (see, e.g., FIGS. 2A-2C, FIG. 4A and FIG. 4B). In embodiments where the head bracing means comprises a flexible strap, closure or harness, the attachment interface 94 of the strap, closure or harness is integrated or bonded with a segment of mating hook and loop material affixed to a frontal surface of the strap, closure or harness (so the frontal surface of the strap, closure or harness height adjustably, securely mates with the rearward-disposed complementary hook and loop anchoring interface provided along the height adjustable anchoring segment at the rear surface of the upper lever arm).

Alternative height-adjustment designs for vertically repositioning the head bracing means include a series or linear array of anchoring holes 90, receptacles or detachable fastener elements arranged at different heights along the longitudinal axis of the upper lever arm (defining the height adjustable anchoring segment of the upper arm), wherein the head bracing means comprises complementary anchoring holes, receptacles or removable fastener elements 96 to allow adjustable anchoring of the head bracing means to the upper lever arm at different brace anchor points over a height adjustment range of between 3-7 inches along the longitudinal axis of the upper lever arm (see, e.g., FIGS. 4C, 4E). Examples of useful, detachable fastener elements within these embodiments include, screws, bolts, brads, pop fittings, snap fasteners, molly fasteners, wire and thread, among others.

Yet another alternative height-adjustment design for vertically repositioning the head bracing means includes a series of anchoring slots 98 arranged at different heights along the longitudinal axis of the upper lever arm 20, wherein the head bracing means comprises a strap portion threadable through the anchoring slots (as illustrated in FIG. 4D) to allow adjustable anchoring of the head bracing means 22′ to the upper lever arm at different brace anchor points over a height adjustment range of between 3-6 inches along the longitudinal axis of the upper lever arm.

As noted above, the front surfaces 44 of the upper and lower lever arms (above and below the angular or arcuate longitudinal anatomical load displacement bend when present), can be substantially planar. In more detailed aspects of the invention, a further novel modification is employed wherein the front surface 44 of the lower lever arm 24 is profiled to be transversely concave, defining a thoracic load distributing transverse arc 104 having a radius of curvature of from 10 inches to 40 inches over at least a portion of the lower lever arm (see, e.g., FIGS. 3D and 7B). Thus, while the lower lever arm may be substantially linear in the longitudinal direction (e.g., along line A-A in FIG. 3A), it can be formed into a near planar curved, or moderately curved, profile in transverse section (illustrated by transverse section B-B in FIGS. 3A and 3D) to afford surprising thoracic load distributing and comfort benefits. In exemplary embodiments the front surface 44 of the lower lever arm 24 is transversely concave defining a thoracic load distributing transverse arc 104 having a radius of curvature of from 15-30 inches, from 16-25 inches, or from 18-22 inches over at least a portion of the lower lever arm. In certain embodiments, the entire front surface of the lower lever arm can be transversely concave, and in more detailed embodiments the lower lever arm transitions from a more deeply concave profile at an upper portion (e.g., adjacent the anatomical load displacement bend 26, when present), to a shallower concave or even planar profile at a lower portion (e.g., at the bottom edge 38 of the lower lever arm). In one illustrative embodiment the thoracic load distributing transverse arc has a radius of curvature at the upper end of the lower lever arm (e.g., nearest to, or coincident with, the anatomical load displacement bend, when present) of approximately 20 inches, while at the bottom end (e.g., the lowest edge) the lower lever arm is more shallowly curved (for example having a radius of curvature greater than 20 inches).

In related embodiments, the front surface 44 of the lower lever arm 24 is thusly concave transversely at a bottom terminus 38 of the lower lever arm, to securely and comfortably engage a mid-lower thoracic portion (defined here as corresponding to thoracic vertebrae T8-T10, as depicted in FIG. 1A) of a user's back 14 and enhance mid-lower thoracic load distribution, whereas in other embodiments the lower lever arm is transversely concave, uniformly or variably, substantially throughout its length (e.g., from an upper terminus of the lower lever arm adjacent the longitudinal anatomical load displacement bend 26 when present, to the bottom terminus of the lower lever arm), to securely and comfortably engage both mid-thoracic (defined here as corresponding to thoracic vertebrae T5-T7, see FIG. 1A) and mid-lower thoracic (T8-T10) portions of a user's back and provide optimal thoracic load distribution to mediate application and transmission of lever and fulcrum forces comfortably throughout the lower lever arm and midsection of the lever member in use and comfortably generate rearward work force against the upper lever arm 20 transmitted through the head-bracing means 22 to oppose frontal flexion loading of the user's head 18. In illustrative embodiments, the front surface of the lower lever arm is uniformly transversely concave throughout its length, defining a thoracic load distributing transverse arc 104 having a radius of curvature of from 18 inches to 22 inches extending from the upper terminus of the lower lever arm adjacent the longitudinal anatomical load displacement bend to the bottom terminus of the lower lever arm.

In other related embodiments, the rigid elongate lever member 12 may additionally be concave at the midsection (between the upper and lower lever arms), which is coincident with the angular or arcuate longitudinal anatomical load displacement bend when present (in which case the midsection of the rigid elongate lever member is frontally concave in both longitudinal and transverse axes).

The profile of the front surface 44 of the rigid lever member 12 is anatomically conceived, designed and manufactured to afford previously unforeseen advantages and operative benefits, whereas the rear surface 40 of the lever member is relatively unconstrained in design and construction, and thus can vary from the front surface in many independent aspects. Nonetheless, the rigid elongate lever member is often beneficially manufactured to have a body thickness that is substantially uniform throughout, whereby the front and rear faces will be profiled substantially parallel throughout. Thus, when the front surface of the rigid elongate lever member is concave at the midsection between the upper and lower lever arms, coincident with the angular or arcuate longitudinal anatomical load displacement bend 26, and thickness of the rigid elongate lever member is substantially uniform, the rear surface of the midsection of the lever member is convex in both longitudinal and transverse dimensions, or substantially dome-shaped, providing enhanced comfort, rigidity and durability of the device. (See FIG. 7A)

Profiling of the upper lever arm 20 is usually substantially flat along most or all of the front surface, whereby there is little or no curvature to the upper lever arm, transversely (e.g., as depicted in FIG. 3F) or longitudinally (e.g., s depicted in FIG. 3B). However, for added longitudinal stiffening and resistance to torsional deformation it is contemplated that the upper lever arm may in some embodiments be transversely curved according to the same parameters and radii of transverse arc curvature ranges described above for the lower lever arm 24.

In further detailed aspects of the invention, the lower lever arm 24 and midsection (coincident with the anatomical load displacement bend 26 when present) of the rigid lever member can be profiled to define a contoured frontal contact surface 46 of the lever member, wherein a width dimension at a midpoint of the midsection 106 (corresponding to section C-C in FIG. 3A), coincident with a midpoint of the longitudinal anatomical load displacement bend when present), is less than a width dimension at a bottom terminus 38 of the lower lever arm. In this configuration, as illustrated in FIGS. 1A and 5 , the frontal contact surfaces 44, 46 are profiled and dimensioned to engage a narrow, mid-thoracic portion of a user's back to fit between medial borders 110 of opposing scapulae, and to engage a wider, mid-lower thoracic portion of the user's back. The net result determined from testing of numerous designs is to optimally mediate application and transmission of lever and fulcrum forces throughout the lower lever arm and midsection of the rigid lever member, whereby in use the device comfortably, reflexively and almost unnoticeably generates rearward force against the upper lever arm transmitted through the head-bracing means to oppose involuntary (due to sleep or fatigue) frontal flexion loading of the user's head.

Exemplifying these embodiments, a rigid elongate lever member may be provided having a width at the midpoint ranging from 3-8 inches, while the corresponding width at the bottom of the lower lever member may range from 4-10 inches. More typically the width of the lever member at the midpoint ranges from about 4-7 inches, and at the bottom of the lower lever member from about 5-9 inches. In illustrative embodiments, the width at the midpoint ranges between 5-6 inches, for example approximately 5.5-5.75 inches, and the width at the bottom ranges between 5.5 inches and 8 inches, for example about 6.5, 6.7 or 6.9 inches.

Other exemplary travel sleep aid devices of the invention employ a rigid elongate lever member sized and dimensioned for placement between a thoracic spinal region of a user's back and an upright seatback surface, having front and back surfaces and comprising upper and lower lever arms, with the lower lever arm comprising a frontally curved section of the lever member having the front surface transversely concave, defining a thoracic load distributing transverse arc having a radius of curvature of from 16 inches to 24 inches over at least a portion of the lower lever arm, wherein the lower lever arm and an adjacent midsection of the rigid lever member define a contoured frontal contact surface of the lever member having a width dimension at the midsection less than a width dimension at a bottom terminus of the lower lever arm. According to this novel combination, the contoured frontal contact surface is profiled and dimensioned to engage a narrow, mid-thoracic portion of a user's back to seat between medial borders of opposing scapulae and engage a wider, mid-lower thoracic portion of the user's back to optimally mediate application, whereby the lower lever arm and midsection collectively optimally distribute and transmit lever and fulcrum forces between a user's back and an opposing, surface of the upright seat back 16, through the lower lever arm 24 and midsection of the rigid lever member during use. This embodiment further includes head-bracing means 22 attached to the upper lever arm adapted to positionally secure the user's head in close proximity to the front surface of the upper lever arm 46. Operationally this embodiment functions to generate and transmit work forces from the lower lever arm and midsection (disposed between the user's mid and mid-lower thoracic back and an upright seat surface) to bias the upper lever arm with rearward work force that responsively opposes frontal flexion loading by the user's head during neck relaxation and sleep.

The novel anatomical, load displacement and load distribution features of the device 10 of the invention operates uniquely to generate dynamic, reflexive and finely responsive lever and fulcrum forces to maintain the user's head 18 in a position of comfortable, upright equilibrium, and to oppose involuntary frontal flexion and lateral flexion and panning movements, when the neck muscles are relaxed during sleep or fatigue. The dynamic load distribution and zonal fulcrum operation features are depicted in FIGS. 1A through 1C, with dynamic load distribution depicted by the solid arrows and the zonal and transient forces depicted by the shaded fields 118 and 118′. Examining FIG. 1B, the lever member 12 is at equilibrium, with no frontal loading by forward flexion of the user's head 18 as represented by ventral/distal uniformity of the shaded regions 118, whereby lever forces are balanced and static, and the “fulcrum” is inoperative or equally load-distributed throughout the lower lever arm 24 and longitudinal anatomical load displacement bend. In contrast, in the loaded configuration as depicted as the shaded regions 118′ in FIGS. 1A and 1C, frontal head flexion of the user creates frontal loading transmitted through the head bracing means 22 to the upper lever arm (see frontal load arrow 116 in FIG. 1A, and the frontal loading zonal force depicted by the shaded field 120 indicating a frontal loading force transmitted to the upper terminal portion 60 of the upper lever arm). This frontal loading in turn mediates dynamic load transfer through the lever member and actuation of the dynamic fulcrum, yielding the transient load shifting and fulcrum operation depicted in FIGS. 1A and 1C, whereby reflexive rearward force is generated and transmitted through the upper lever arm to oppose the frontal force and stabilize the user's head position. This novel, reflexive loading and load distribution design operates through a dynamic, zonal fulcrum 118 (shaded transient load distribution fields illustrated in FIGS. 1A-1C), wherein the fulcrum is reflexive to loading and generally disposed over a contact surface 122 of the device 10 (spanning bracket 122 in FIG. 1A, generally limited to the lower lever arm 24 and anatomical load displacement bend 26) and a region of contact of the user's back 124 with the device (i.e., the portion of back in contact with the device is represented by bracket 124 in FIG. 1A, and generally corresponds to approximately spanning thoracic vertebrae T4-T10, or therebetween). As the zonal fulcrum (shaded field) and load distribution arrows FIGS. 1A and 1C indicate, an approximate fulcrum center point 126 (indicated by the long arrow in FIG. 1A) corresponds closely to the position of the anatomical load displacement bend 26 on the device 10, and in turn to a position on the user's back approximately between thoracic vertebrae T5 and T6).

The rigid elongate lever member 12 of the invention and head brace 22 height adjustment features are designed to accommodate a wide range of prospective human users, as described herein being adapted for comfortable use by individuals of heights ranging from a 20-percentile adult female height, to an 80-percentile male height. To accommodate this range and provide for ease of storage, transport and deployment, the rigid elongate lever member has an overall length dimension 130 (FIG. 3A) of less than 30 inches. More typically the rigid elongate lever member has an overall length dimension of between 12-25 inches. In exemplary embodiments, the rigid elongate lever member has an overall length dimension of between 14-22 inches, or between 16-20 inches, for example about 18 inches.

In other dimensional design aspects, when the rigid elongate lever member incorporates an anatomical load displacement bend 26, when the elongate lever member incorporates an anatomical load displacement bend 26, the elongate lever member is often positioned below a longitudinal midpoint of the rigid elongate lever member, functionally biasing the resulting, shorter lower lever arm 24 with respect to location of an operative fulcrum, which bias is typically accompanied by a wider profile and more aggressive stiffening features (mentioned below) as compared to the longer upper lever arm. The comparatively overwhelming lever and fulcrum stabilizing forces generated against the lower lever member by opposition of the user's massive thoracic back region against the lever member and seat back biases loading of the lower lever member, functionally allows the lower lever arm to be shorter. In this way, the lower lever arm functions in terms of lever mechanics comparable to the fixed end of a diving board; it is effectively unmovable with respect to the user and seat. In this configuration, featuring a shorter lower lever arm, the lower lever arm has a length (defined from a midpoint 106 of the anatomical load displacement bend 26 when present, to a bottom terminus 38 of the lower lever arm), that is no greater than 45% of a total length dimension 130 of the rigid elongate lever member. In related embodiments, the lower lever arm has a length that is between 25% to 40% of a total length dimension of the rigid elongate lever member. In exemplary embodiments, the lower lever arm has a length between about 34% to 38%, for example about 36%, of the total length dimension of the rigid elongate lever member.

Yet another novel aspect of the invention is the employment of stiffening construction or stiffening elements to afford enhanced rigidity to the rigid elongate lever member 12, concurrent with the provision of novel shape, profile and size features described herein. In certain embodiments, the rigid elongate lever member further comprises one or more longitudinal stiffening members 136 for example integral steel, glass fiber, or other rigid support elements fabricated within or inserted into the rigid elongate lever member and oriented for resistance of longitudinal deformation of the lever member. In exemplary embodiments, the stiffening member or members may be constructed from one or a combination of stiffening ribs, stiffening channels, stiffening creases, stiffening grids, and disposed on the front and/or back surfaces, or on the longitudinal edges of the rigid elongate lever member.

In related embodiments depicted in FIGS. 6A-6F, one or more longitudinal stiffening rib(s) 122 may be integrated with (e.g., unitarily cast as part of, or separately manufactured and welded or glued to) the rigid elongate lever member 12, constructed and oriented for longitudinal stiffening of the rigid elongate lever member. In exemplary embodiments, one or multiple longitudinal stiffening rib(s) extend from at least a portion of the back face 40 of the rigid elongate lever member. The longitudinal stiffening ribs may extend at least throughout a midsection of the rigid elongate lever member (e.g., corresponding to a longitudinal span of the anatomical load displacement bend when present), optionally from left and right sides (138 and 140, respectively) of the back face of the rigid elongate lever member.

In illustrative embodiments, the travel sleep aid device of the invention includes longitudinal stiffening ribs 136 extending rearward from left 138 and right 140 sides of the back face 40 of the rigid elongate lever member 12, typically spanning lengthwise over 35% to 100% of the left and right sides of the back face of the rigid elongate lever member. In certain embodiment the longitudinal stiffening ribs extend from substantially the entire length of the left and right sides of the back face of the rigid elongate lever member. Given the load requirements of this functional system, the need for stiffening features diminishes as a function of longitudinal distance from the operative fulcrum.

In related aspects of the invention, novel stiffening rib design employs a non-uniform rib height at different points of the rigid elongate lever member, for example wherein the longitudinal stiffening ribs 136 have a maximum height dimension 142 at a midpoint 106 of the middle or mid-lower curved section 48 of the rigid elongate lever member and diminish in height from the midpoint in an angular or gradual curved height reduction profile toward top and bottom termini 32, 38 of the upper and lower lever arms 20, 24, respectively (i.e., the ribs are of a substantially lesser height at the termini than at the midsection midpoint). In exemplary embodiments, the longitudinal stiffening ribs may be between about 0.3 inches to 1.8 inches in height at the midsection midpoint, and less than 0.7 inches at the upper and lower arm termini. Alternatively, the longitudinal stiffening ribs may be between about 0.5 inches to 1.5 inches in height at the midsection midpoint, and less than 0.5 inches at the termini. Additional designs comprehend between about 0.7 inches to 1.0 inches, or between about 0.8 inches to 0.9 inches, in height at the midsection midpoint, and less than about 0.3 inches at the termini.

When stiffening ribs 136 are integrated in the rigid elongate lever member 12 construction, the ribs may extend perpendicularly or nearly perpendicularly rearward from the back 40 (typically from the back sides 138, 140) of the rigid elongate lever member, for maximum stiffening effectiveness. Alternatively, yet another novel design concept of the invention incorporates stiffening ribs extending from the back sides of the rigid lever member, wherein at their highest points (corresponding to the middle or mid-lower midsection 48 midpoint 106) the stiffening ribs extend rearward and laterally from the back surface 40 at an obtuse angle 148 of at least 100 degrees relative to a horizontal stacking axis of the rigid elongate member (see, e.g., FIGS. 6C-6F). The horizontal stacking axis is defined as a line drawn between lateral contact points 146 (see FIG. 6A) or seating edges of a front surface 46 (that may be planar or curved as described) of the rigid elongate lever member, providing for stable, compact nested stacking of multiple elongate lever members on top of one another, for efficient storage and shipping (without unacceptable loss of rigidity afforded by the stiffening ribs). In more detailed embodiments, the stiffening ribs at their highest points 142 extend rearward and laterally from the back surface at an obtuse angle 148 (see FIG. 6F) of between 110 degrees and 120 degrees relative to the horizontal stacking axis of the rigid elongate member. In exemplary embodiments, the stiffening ribs at their highest points extend rearward and laterally from the back surface at an obtuse angle of between 105 degrees and 115 degrees, or between 110 degrees and 115 degrees, relative to the horizontal stacking axis of the rigid elongate lever member (likewise providing for stable stacking and efficient storage and shipping, without unacceptable loss of rigidity afforded by the stiffening ribs).

In related embodiments, the stiffening ribs 136 may be further modified at a top terminus 32 of the upper lever arm 20 so that, in addition to having a substantially lower height compared to the midsection rib height, they extend rearward from the back surface at a perpendicular or nearly perpendicular angle 150 (see FIG. 6D), for example at an angle between about 90 degrees to 99 degrees relative to the horizontal stacking axis). According to this novel design, the perpendicularity of ribs at the top terminus afford increased longitudinal stiffening (compared to the more obtusely angled rib orientation at the midsection) to compensate for the lesser height of the stiffening ribs at this portion of the lever member. Additionally, and distinctly, the sharper angularity and reduced height of the ribs at the upper lever arm terminus (compared to the middle or mid-lower section midpoint 106) combine to afford further stacking stability for enhanced storage, handling and shipping. Briefly, the ribs here are designed with a spacing height 152 at the top terminus of the upper lever arm, selected to correspond approximately to a stacking separation distance 154 (FIG. 6F) between opposing surfaces of nested lever members at the midsection midpoint, whereby the stiffening ribs at the top terminus of one stacked lever member seat stably atop a corresponding back surface of a lower-stacked lever member to further secure multiple nested lever members in a compact, stable stacked array for improved storage and shipping. Within exemplary embodiments, the spacing height 152 of stiffening ribs at the top terminus 32 of the upper lever arm is selected within a range of about 0.10 inches to 0.30 inches, or about 0.15 inches to 0.25 inches, for example about 0.17 inches, corresponding approximately to a separation distance determined between opposing surfaces of nested lever members at the midsection midpoint are each (dependent on the obtuseness of rib angles at peak rib height, and thickness of the lever member body). By virtue of these novel combined features, large numbers of manufactured rigid elongate lever members can be stably stacked one atop the other, beginning by placing a first lever member front face down on a flat stacking surface, building up to large numbers of units stably nested together in a substantially vertical balanced stack.

In a related, illustrative embodiment, the invention thus provides a travel sleep aid device 10 for stably and comfortably restraining a head position of an upright seated human user, comprising a rigid

-   -   elongate lever member 12 sized and dimensioned for placement         between a thoracic spinal region of a user's back and an upright         seatback 16 surface, having front 44 and back 40 surfaces and         optionally being wider at a top edge 32 of the lever member than         at a bottom edge 38 of the lever member, combined with         head-bracing means 22 attached to an upper terminal portion 60         (or brace-anchoring segment) of the rigid elongate lever member         to positionally secure a user's head 18 relative thereto, with         longitudinal stiffening ribs 136 extending rearward from right         and left sides 138, 140 of the back surface of the rigid         elongate lever member, the stiffening ribs being highest at a         defined fulcrum point, section or region of the rigid elongate         lever member and lower at its top and bottom edges, wherein at         their highest points the stiffening ribs extend rearward and         laterally from the back surface (at an obtuse angle 148 of at         least 100 degrees relative to a horizontal stacking axis of the         rigid elongate member), whereby the stiffening ribs mediate         stable, compact stacking of multiple elongate lever members for         efficient storage and shipping without unacceptable loss of         rigidity provided by the stiffening ribs. In more detailed         embodiments, the shortened stiffening ribs at the top terminus         of the lever member extend rearward from the back surface at a         perpendicular or nearly perpendicular angle 150 (typically         between 90-99 degrees relative to the horizontal stacking axis)         to afford substantial stiffening (despite the reduced height of         the stiffening ribs at this portion of the lever member), and         optionally have a determined nesting height (typically between         0.10 inches and 0.30) inches at the top terminus corresponding         closely or exactly to a separation distance between opposing         surfaces of nested lever members at the middle region, whereby         the stiffening ribs at the top terminus of one stacked lever         member seat stably atop a corresponding back surface of a         lower-stacked lever member to further secure multiple nested         lever members in a compact, stable stacked array for improved         storage and shipping.

Within additional aspects of the invention, the rigid elongate lever member 12 is additionally strengthened or reinforced against torsional forces, for example as generated by the user's head driven laterally (flexed) or twisted (panning motion) by turbulence or adverse road conditions. In addition to increasing the stiffness of the rigid elongate lever member, to support the head under ventral/dorsal loading, various stiffening rib designs as described and contemplated herein will also contribute stiffness under torsional loads caused by head motion to the left and right. This type of force is negligible for air travel in cases apart from severe turbulence, however inadvertent left/right head motion is prevalent in auto and bus travel. The various rib designs described here resist such head movements by resisting torsional deformation of the lever member, or at least of the upper lever arm. Additionally, the transverse curvature described through the midsection and lower portion of the lever member additionally stiffens the lever arm to oppose torsional force/deformation, further stabilizing the user's head positionally to avoid or minimize involuntary lateral head flexion and panning movements.

Yet additional aspects of the invention provide novel and uniquely effective methods for restraining the head of a fatigued or sleeping person seated in an upright position to prevent involuntary forward and lateral flexion of the head. According to these methods, a seated user positions a rigid elongate lever member 12 between their thoracic spinal region and an upright seatback 16 surface, the lower lever member having front 44 and back 40 surfaces and comprising upper and lower lever arms 20, 24. The upper lever arm is typically narrower than the lever arm, and a midsection of the lever member optionally includes an angular or arcuate longitudinal anatomical load displacement bend 26 of the frontal surface (disposed between the upper and lower lever arms). The user further adjusts the lower lever arm, thus defining an operable fulcrum position of the rigid elongate lever member user-selected to a comfortable, optimum force balancing position, wherein the longitudinal anatomical load displacement bend is positioned between the seat surface and a mid-thoracic portion of the person's back, and the lower lever arm is positioned between the seat surface and a mid-lower-thoracic portion of the person's back. The user additionally engages head-bracing means 22 attached to the upper lever arm to positionally secure the person's head relative to the upper lever arm, whereby rearward work forces against the upper lever arm are transmitted through the head-bracing means to oppose frontal flexion loads of the user's head when neck muscles are relaxed during fatigue or sleep.

Further detailed methods of the invention employ the foregoing steps, refined by positioning the longitudinal anatomical load displacement bend between the seat surface and an optimal anatomical fulcrum position spanning or disposed between the person's fourth-seventh thoracic vertebrae. According to exemplary methods, the longitudinal anatomical load displacement bend is typically positioned between the seat surface and an optimal anatomical fulcrum position spanning or disposed between the person's fifth-sixth thoracic vertebrae. Frequently, the longitudinal anatomical load displacement bend is positioned between the seat surface and an optimal anatomical fulcrum position spanning or disposed between the person's fifth-sixth thoracic vertebrae.

In related methods, the rigid elongate lever member makes contact with the person's back spanning positions of at least fifth through ninth thoracic vertebrae. More commonly, contact of the rigid elongate lever member with the user's back is restricted to positions corresponding to between the third and eleventh thoracic vertebrae.

A primary component of the inventive device, the rigid elongate lever member 12, can be constructed from any of a wide range of suitable, rigid formable materials, for example plastics, resins, woods, metals, fiberglass, or any other suitable material capable of being fabricated to meet the above described structural and performance specifications. All thusly useful production materials and processes known in the art are therefore comprehended within the scope of the instant disclosure and claims.

To optimally fulfill the design, construction and performance requirements of the rigid elongate lever member 12, however, the most reliable, facile and economical production means is contemplated to involve unitary construction via molded polymer technology. Exemplary production methods and materials include polymer injection molding, for example using polycarbonate acrylic butyl polystyrene (PC/ABS), Polyethylene (PE), Polyvinylchloride (PVC), or Polyamide (PA) “nylon” (typically provided as beads/pellets) or another suitable plastic/polymer feedstock. Alternatively, the rigid elongate lever member can be fabricated using these and other plastics by vacuum-forming, pressure-forming, drape-forming or other deformation methods, optionally combined with machining or milling technologies as are well known to skilled artisans practicing in related fields to the invention. According to less desirable methods (at least in terms of efficiency and cost of production), the rigid elongate lever member may alternatively be fabricated using casting or hand lay-up methods, for example using fiberglass, carbon fiber, natural or synthetic laminates, in combination with polyester, epoxy or other binding resins and polymers. Additional processes comprehended for manufacture of the rigid elongate lever member include “rapid prototype processes” (e.g., 3-D printing “SLA”, “SLS”, and “FDM”).

The invention is described herein for illustrative purposes only, understanding that economy of description is encouraged by the Patent Laws. Accordingly, persons skilled in the art will appreciate that further aspects, embodiments, improvements and equivalents are comprehended fully within the scope of the invention, which is limited only by the following claims. 

1. A travel sleep aid device for stably and comfortably restraining a head position of an upright seated human user, comprising: A rigid elongate lever member sized and dimensioned for placement between a thoracic spinal region of a user's back and an upright seatback surface, the lever member having front and back surfaces and comprising upper and lower lever arms, wherein a width dimension of the upper lever arm is less than a width dimension of the lower lever arm, and wherein a midsection of the lever member defines an angular or arcuate longitudinal anatomical load displacement bend of the frontal surface between the upper and lower lever arms; and Head-bracing means attached to the upper lever arm adapted to positionally secure a user's head relative to the upper lever arm, whereby rearward forces against the upper lever arm are transmitted through the head-bracing means to oppose frontal flexion loads of the user's head.
 2. The travel sleep aid device of claim 1, wherein the longitudinal anatomical load displacement bend comprises at least a 5-degree angle or curve of the frontal surface between the upper and lower lever arms, whereby a frontal longitudinal axis of the upper lever arm diverges frontally at least 5 degrees from a frontal longitudinal axis of the lower lever arm.
 3. The travel sleep aid device of claim 1, wherein the longitudinal anatomical load displacement bend comprises an angle or curve of the inner surface no greater than 30 degrees between an upper end of the upper lever arm and a lower end of the lower lever arm, whereby a frontal longitudinal axis of the upper lever arm diverges frontally no more than 30 degrees from a frontal longitudinal axis of the lower lever arm.
 4. The travel sleep aid device of claim 1, wherein the longitudinal anatomical load displacement bend comprises an angle or curve of the inner surface within a range of 10-20 degrees between an upper end of the upper lever arm and a lower end of the lower lever arm, whereby a frontal longitudinal axis of the upper lever arm diverges frontally within a range of degrees from a frontal longitudinal axis of the lower lever arm.
 5. The travel sleep aid device of claim 1, wherein the longitudinal anatomical load displacement bend comprises an angle or curve of the inner surface within a range of 12-18 degrees between an upper end of the upper lever arm and a lower end of the lower lever arm, whereby a frontal longitudinal axis of the upper lever arm diverges frontally within a range of 12-18 degrees from a frontal longitudinal axis of the lower lever arm.
 6. The travel sleep aid device of claim 1, wherein the longitudinal anatomical load displacement bend comprises an angle or curve of the inner surface of approximately 16 degrees between an upper end of the upper lever arm and a lower end of the lower lever arm, whereby a frontal longitudinal axis of the upper lever arm diverges frontally about 16 degrees from a frontal longitudinal axis of the lower lever arm.
 7. The travel sleep aid device of claim 1, wherein the longitudinal anatomical load displacement bend is a sharp angular bend disposed over a short distance of between about 0-inches between the upper and lower lever arms, defining a sharp angled bend of the frontal surface between the upper and lower lever arms.
 8. The travel sleep aid device of claim 1, wherein the longitudinal anatomical load displacement bend is a tight arcuate bend disposed over a distance of between about 0.25-inches between the upper and lower lever arms, defining a tight curved frontal surface bend between the upper and lower lever arms.
 9. The travel sleep aid device of claim 1, wherein the longitudinal anatomical load displacement bend is a relaxed arcuate bend disposed over a distance of between about 0.75-4.0 inches between the upper and lower lever arms, defining a shallow-arc curved frontal surface bend between the upper and lower lever arms.
 10. The travel sleep aid device of claim 1, wherein terminal segments of the upper and lower lever arms above and below the angled or curved longitudinal anatomical load displacement bend are substantially linear along their frontal, longitudinal axes
 11. The travel sleep aid device of claim 1, wherein the head-bracing means comprises a strap or harness permanently or removably attached to the upper lever arm sized and configured to surround the user's head and comfortably secure and restrain the user's head relative to the upper lever arm.
 12. The travel sleep aid device of claim 1, wherein the head-bracing means comprises a flexible textile strap or closure that anchors to an upper, brace-anchoring segment of the upper lever arm and extends therefrom to surround the user's head in secure contact with at least a frontal portion of the user's head.
 13. The travel sleep aid device of claim 1, wherein the head-bracing means comprises an elastic strap in the form of a loop sized and dimensioned to elastically fit over and firmly embrace the user's head, permanently or removably affixed to the upper lever arm.
 14. The travel sleep aid device of claim 1, wherein the head bracing means comprises a flexible textile strap or closure attached to an upper, brace-anchoring segment of the upper lever arm and extending therefrom, sized and dimensioned to surround the user's head in secure contact with at least a frontal portion of the user's head.
 15. The travel sleep aid device of claim 1, wherein the head bracing means comprises a flexible textile strap or closure positioned, sized and dimensioned to comfortably and securely seat against a forehead of the user.
 16. The travel sleep aid device of claim 15, wherein the flexible textile strap or closure is between about 1-3 inches in width to seat comfortably and securely seat against the forehead.
 17. The travel sleep aid device of claim 1, wherein the head bracing means comprises a flexible textile strap or closure made of a woven, knitted or braided natural or synthetic fiber material.
 18. The travel sleep aid device of claim 17, wherein the fiber material is selected from cotton, wool, hemp, bamboo or another natural textile fiber.
 19. The travel sleep aid device of claim 17, wherein the fiber material is selected from nylon, polyester, polypropylene or other synthetic fiber.
 20. The travel sleep aid device of claim 1, wherein the head bracing means comprises a flexible, elastic or semi-elastic strap or closure.
 21. The travel sleep aid device of claim 1, wherein the head bracing means comprises a flexible, elastic or semi-elastic strap or closure formed at least in part of latex, natural rubber or neoprene (polychloroprene).
 22. The travel sleep aid device of claim 21, wherein the strap or closure comprises a latex, natural rubber or neoprene layer covered on at least one surface with a bonded textile layer for comfort and breathability.
 23. The travel sleep aid device of claim 21, wherein the head bracing means comprises a flexible, semi-elastic strap or closure formed of nylon 1 neoprene or nylon 2 neoprene covered on one or both sides of the strap or closure with nylon fabric bonded to the neoprene for comfort.
 24. The travel sleep aid device of claim 21, wherein the head bracing means comprises a flexible, semi-elastic strap or closure having at least a portion of an inner surface of the strap or closure adapted for contacting and engaging a user's forehead comprising open celled neoprene for improved breathability and enhanced friction to securely engage and restrain the forehead.
 25. The travel sleep aid device of claim 1, wherein the head-bracing means comprises an adjustable-length strap or closure that can be tensioned or loosened to accommodate different sized user's heads, and to increase or decrease friction forces mediating secure contact of the strap or closure with the user's head.
 26. The travel sleep aid device of claim 1, wherein the head-bracing means comprises a flexible strap and strap-length adjustment means integral to a strap assembly or mounted to or integrated within the upper lever arm.
 27. The travel sleep aid device of claim 25, wherein the strap length adjustment means comprises a cam buckle or tri-glide slide anchored to one end of a strap assembly, the buckle or slide adapted to adjustably receive and secure a free strap end to mediate secure shortening and lengthening of the strap to adjust fit and tension of the strap relative to the user's head.
 28. The travel sleep aid device of claim 1, wherein the head-bracing means comprises left and right closure strap ends anchored to the upper lever arm, the strap ends respectively sized and dimensioned to surround a portion of the user's head and to meet or overlap alongside or in front of the user's head, and having adjustable coupling means to secure the strap ends together to form a secure, length-adjustable closure.
 29. The travel sleep aid device of claim 27, wherein the left and right strap ends incorporate terminal strap segments of mating hook and loop material on opposing faces that interlock securely when the strap ends are overlapped, the left and right strap ends and terminal hook and loop segments being sized and dimensioned to afford a range of closed strap circumferences to accommodate different head sizes and strap tensions.
 30. The travel sleep aid device of claim 1, wherein the head bracing means comprises a flexible textile strap or closure anchored to the upper lever arm at one or more side or rear brace anchor point(s), whereby in use left and right anchoring segments of the strap or closure are secured or tensioned against left and right sides of the upper lever arm, affording improved comfort and positional stability.
 31. The travel sleep aid device of claim 29, wherein the upper lever arm has a width of from 1 inch to 6 inches at a height corresponding to a height of the brace anchor point(s), mediating separation of the left and right anchoring segments of the strap or closure by a corresponding width of 1-6 inches.
 32. The travel sleep aid device of claim 29, wherein the upper lever arm has a width of from 2 inches to 5 inches at a height corresponding to a height of the brace anchor point(s), mediating separation of the left and right anchoring segments of the strap or closure by a corresponding width of 2-5 inches.
 33. The travel sleep aid device of claim 29, wherein the upper lever arm has a width of from 3 inches to 4 inches at a height corresponding to a height of the brace anchor point(s), mediating separation of the left and right anchoring segments of the strap or closure by a corresponding width of 3-4 inches
 34. The travel sleep aid device of claim 1, further comprising head brace height adjustment means for repositioning the head bracing means to different brace anchor points along a longitudinal axis of the upper lever arm to accommodate height variation among different users.
 35. The travel sleep aid device of claim 33, wherein the head brace height adjustment means provides alternate, user selectable brace anchor points over a height adjustability range of between 1-7 inches along the longitudinal axis of the upper lever arm.
 36. The travel sleep aid device of claim 33, wherein the head brace height adjustment means provides alternate, user selectable brace anchor points over a height adjustability range of between 2-5 inches along the longitudinal axis of the upper lever arm.
 37. The travel sleep aid device of claim 33, wherein the head brace height adjustment means provides alternate, user selectable brace anchor points over a height adjustability range of between 3-4 inches along the longitudinal axis of the upper lever arm.
 38. The travel sleep aid device of claim 33, wherein the head brace height adjustment means operates by detachment and reattachment of the head bracing means to different brace anchor points along the longitudinal axis of the upper lever arm.
 39. The travel sleep aid device of claim 33, wherein the head brace height adjustment means by positional re-adjustment of the head bracing means along the longitudinal axis of the upper lever arm without detaching the head bracing means from the upper lever arm.
 40. The travel sleep aid device of claim 33, wherein the head brace height adjustment means comprises an elongate, adjustable anchoring interface of hook and loop material affixed to the rear surface of the upper lever arm and a segment of mating hook and loop material affixed to a frontal surface of an opposing attachment interface of the head bracing means.
 41. The travel sleep aid device of claim 39, wherein the head bracing means comprises a flexible strap with a rear attachment interface of the strap having a segment of mating hook and loop material affixed to a frontal surface of the strap.
 42. The travel sleep aid device of claim 33, wherein the head brace height adjustment means comprises a series of anchoring holes, receptacles or detachable fastener elements arranged at different heights along the longitudinal axis of the upper lever arm, and wherein the head bracing means comprises complementary anchoring holes, receptacles or removable fastener elements to allow adjustable anchoring of the head bracing means to the upper lever arm at different brace anchor points over a height adjustment range of between 3-7 inches along the longitudinal axis of the upper lever arm.
 43. The travel sleep aid device of claim 41, wherein the detachable fastener elements are selected from screws, bolts, brads, pop fittings, snap fasteners, molly fasteners, wire and thread.
 44. The travel sleep aid device of claim 33, wherein the head brace height adjustment means comprises a series of anchoring slots arranged at different heights along the longitudinal axis of the upper lever arm, and wherein the head bracing means comprises a strap portion threadable through the anchoring slots to allow adjustable anchoring of the head adjustment means to the upper lever arm at different brace anchor points over a height adjustment range of between 3-6 inches along the longitudinal axis of the upper lever arm.
 45. The travel sleep aid device of claim 1, wherein front surfaces of the upper and lower lever arms, above and below the angular or arcuate longitudinal anatomical load displacement bend, are substantially planar.
 46. The travel sleep aid device of claim 1, wherein a front surface of the lower lever arm is transversely concave, defining a thoracic load distributing transverse arc having a radius of curvature of from 10 inches to 40 inches over at least a portion of the lower lever arm.
 47. The travel sleep aid device of claim 1, wherein a front surface of the lower lever arm is transversely concave, defining a thoracic load distributing transverse arc having a radius of curvature of from 15 inches to 30 inches over at least a portion of the lower lever arm.
 48. The travel sleep aid device of claim 1, wherein a front surface of the lower lever arm is transversely concave, defining a thoracic load distributing transverse arc having a radius of curvature of from 16 inches to 25 inches over at least a portion of the lower lever arm.
 49. The travel sleep aid device of claim 1, wherein a front surface of the lower lever arm is transversely concave, defining a thoracic load distributing transverse arc having a radius of curvature of from 18 inches to 22 inches over at least a portion of the lower lever arm.
 50. The travel sleep aid device of claim 47, wherein the front surface of the lower lever arm is concave at a bottom terminus of the lower lever arm to securely and comfortably engage a mid-lower thoracic portion of a user's back and provide optimal mid-lower thoracic load distribution.
 51. The travel sleep aid device of claim 47, wherein the front surface of the lower lever arm is concave substantially throughout its length, from an upper terminus of the lower lever arm adjacent to or coincident with the longitudinal anatomical load displacement bend to a bottom terminus of the lower lever arm, to securely and comfortably engage both mid-thoracic and mid-lower thoracic portions of a user's back and provide optimal thoracic load distribution to optimally mediate application and transmission of lever and fulcrum forces throughout the lower lever arm and midsection in use to comfortably generate rearward force against the upper lever arm transmitted through the head-bracing means to oppose frontal flexion loading of the user's head.
 52. The travel sleep aid device of claim 51, wherein the front surface of the lower lever arm is uniformly transversely concave throughout its length, defining a thoracic load distributing transverse arc having a radius of curvature of from 18 inches to 22 inches extending from the upper terminus of the lower lever arm adjacent the longitudinal anatomical load displacement bend to the bottom terminus of the lower lever arm.
 53. The travel sleep aid device of claim 47, wherein the rigid elongate lever member is additionally concave at the midsection between the upper and lower lever arms, coincident with the angular or arcuate longitudinal anatomical load displacement bend, whereby the midsection of the rigid elongate lever member is frontally concave in both longitudinal and transverse dimensions.
 54. The travel sleep aid device of claim 1, wherein a thickness of the rigid elongate lever member is substantially uniform throughout, whereby the front and rear faces are profiled substantially parallel throughout.
 55. The travel sleep aid device of claim 47, wherein the front surface of the rigid elongate lever member is additionally concave at the midsection between the upper and lower lever arms, coincident with the angular or arcuate longitudinal anatomical load displacement bend, and wherein a thickness of the rigid elongate lever member is substantially uniform throughout, whereby the front and rear faces are profiled substantially parallel throughout, whereby the rear surface of the midsection of the lever member is convex in both longitudinal and transverse dimensions, or substantially dome-shaped, providing enhanced comfort, rigidity and durability of the device.
 56. The travel sleep aid device of claim 47, wherein the upper lever arm is substantially flat, having no less than a 50-inch radius of curvature.
 57. The travel sleep aid device of claim 1, wherein the lower lever arm and midsection of the rigid lever member define a contoured frontal contact surface of the lever member, wherein a width dimension at a midpoint of the midsection corresponding to a midpoint of the longitudinal anatomical load displacement bend, is less than a width dimension at a bottom terminus of the lower lever arm, whereby the contoured frontal contact surface is profiled and dimensioned to engage a narrow, mid-thoracic portion of a user's back to fit between medial borders of opposing scapulae, and to engage a wider, mid-lower thoracic portion of a user's back, to optimally mediate application and transmission of lever and fulcrum forces throughout the lower lever arm and midsection of the rigid lever member in use to comfortably generate rearward force against the upper lever arm transmitted through the head-bracing means to oppose frontal flexion loading of the user's head.
 58. The travel sleep aid device of claim 57, wherein the width of the rigid elongate lever member at the midsection midpoint is within a range of from 3-7 inches.
 59. The travel sleep aid device of claim 57, wherein the width of the rigid elongate lever member at the midsection midpoint is within a range of from 5-6 inches.
 60. The travel sleep aid device of claim 57, wherein the width of the rigid elongate lever member at the midsection midpoint is within a range of from 4 inches to 10 inches.
 61. The travel sleep aid device of claim 57, wherein the width at the bottom terminus of the lower lever arm is within a range of from 5 inches to 9 inches.
 62. The travel sleep aid device of claim 57, wherein the width at the bottom terminus of the lower lever arm is within a range of from 5.5 inches to 8 inches.
 63. The travel sleep aid device of claim 57, wherein the width at the bottom terminus of the lower lever arm is between about 6.5-7.0 inches.
 64. A travel sleep aid device for stably and comfortably restraining a head position of an upright seated human user, comprising: A rigid elongate lever member sized and dimensioned for placement between a thoracic spinal region of a user's back and an upright seatback surface, the lever member having front and back surfaces and comprising upper and lower lever arms, the lower lever arm comprising a frontally curved section of the lever member having the front surface transversely concave, defining a thoracic load distributing transverse arc having a radius of curvature of from 16 inches to 24 inches over at least a portion of the lower lever arm, wherein the lower lever arm and an adjacent midsection of the rigid lever member define a contoured frontal contact surface of the lever member having a width dimension at the midsection less than a width dimension at a bottom terminus of the lower lever arm, whereby the contoured frontal contact surface is profiled and dimensioned to engage a narrow, mid-thoracic portion of a user's back to seat between medial borders of opposing scapulae and engage a wider, mid-lower thoracic portion of a user's back to optimally mediate application, distribution and transmission of lever and fulcrum forces between a user's back and an opposing, upright seat surface through the lower lever arm and midsection of the rigid lever member during use; and Head-bracing means attached to the upper lever arm adapted to positionally secure a user's head relative to the upper lever arm, whereby rearward work forces generated and transmitted by the lower lever arm and midsection disposed between the user's mid and mid-lower thoracic back and the upright seat surface bias the upper lever arm with finely balanced, rearward force that responsively opposes frontal flexion loading by the user's head during neck muscle relaxation and sleep.
 65. The travel sleep aid device of claim 1, wherein the rigid elongate lever member has an overall length dimension of less than 30 inches.
 66. The travel sleep aid device of claim 1, wherein the rigid elongate lever member has an overall length dimension of between 12-25 inches.
 67. The travel sleep aid device of claim 1, wherein the rigid elongate lever member has an overall length dimension of between 14-22 inches.
 68. The travel sleep aid device of claim 1, wherein the rigid elongate lever member has an overall length dimension of between 16-20 inches.
 69. The travel sleep aid device of claim 1, wherein the rigid elongate lever member has an overall length dimension of about 18 inches.
 70. The travel sleep aid device of claim 1, wherein a midpoint of the anatomical load displacement bend is biased toward the lower lever arm, being positioned below a longitudinal midpoint of the rigid elongate lever member, whereby the upper lever arm is longer than the lower lever arm.
 71. The travel sleep aid device of claim 70, wherein the lower lever arm has a length, from the anatomical load displacement bend midpoint to a bottom terminus of the lower lever arm, that is less than 45% of a total length dimension of the rigid elongate lever member.
 72. The travel sleep aid device of claim 70, wherein the lower lever arm has a length, from the anatomical load displacement bend midpoint to a bottom terminus of the lower lever arm, that is between 25% to 40% of a total length dimension of the rigid elongate lever member.
 73. The travel sleep aid device of claim 70, wherein the lower lever arm has a length, from the anatomical load displacement bend midpoint to a bottom terminus of the lower lever arm, that is between 34% to 38% of a total length dimension of the rigid elongate lever member.
 74. The travel sleep aid device of claim 70, wherein the lower lever arm has a length, from the anatomical load displacement bend midpoint to a bottom terminus of the lower lever arm, that is about 36% of a total length dimension of the rigid elongate lever member.
 75. The travel sleep aid device of claim 1, wherein the rigid elongate lever member further comprises one or more stiffening member(s).
 76. The travel sleep aid device of claim 75, wherein the stiffening member(s) is/are selected from integral steel, glass fiber, or other rigid support elements fabricated within or inserted into the rigid elongate lever member.
 77. The travel sleep aid device of claim 75, wherein the stiffening member(s) is/are constructed from stiffening ribs, stiffening channels, stiffening creases, stiffening grids or stiffening honeycomb structural elements disposed within the rigid elongate lever member or integrated with one or both of the front and/or back surfaces of the rigid elongate lever member.
 78. The travel sleep aid device of claim 75, wherein the stiffening member(s) is/are constructed and oriented for longitudinal stiffening of the rigid elongate lever member.
 79. The travel sleep aid device of claim 75, wherein the stiffening member(s) comprise(s) one or more longitudinal rib(s) extending from at least a portion of the back face of the rigid elongate lever member.
 80. The travel sleep aid device of claim 75, having multiple longitudinal stiffening ribs extending from at least a portion of the back face of the rigid elongate lever member.
 81. The travel sleep aid device of claim 75, having longitudinal stiffening ribs extending from left and right sides of the back face of the rigid elongate lever member, at least throughout a midsection of the rigid elongate lever member corresponding to a longitudinal span of the anatomical load displacement bend.
 82. The travel sleep aid device of claim 81, having longitudinal stiffening ribs extending rearward from left and right sides of the back face of the rigid elongate lever member.
 83. The travel sleep aid device of claim 82, wherein the longitudinal stiffening ribs extend from 35% to 100% of a full length of the left and right sides of the back face of the rigid elongate lever member.
 84. The travel sleep aid device of claim 83, wherein the longitudinal stiffening ribs extend from substantially the entire length of the left and right sides of the back face of the rigid elongate lever member.
 85. The travel sleep aid device of claim 82, wherein the longitudinal stiffening ribs are highest at a midpoint of the midsection of the rigid elongate lever member and diminish in height from said midpoint in an angular or gradual curved height reduction profile toward top and bottom termini of the upper and lower lever arms respectively where they are of a substantially lesser height than at the midsection midpoint, or absent.
 86. The travel sleep aid device of claim 85, wherein the longitudinal stiffening ribs are between about 0.3 inches to 1.8 inches in height at the midsection midpoint.
 87. The travel sleep aid device of claim 85, wherein the longitudinal stiffening ribs are between about 0.5 inches to 1.5 inches in height at the midsection midpoint.
 88. The travel sleep aid device of claim 85, wherein the longitudinal stiffening ribs are between about 0.7 inches to 1.0 inches in height at the midsection midpoint.
 89. The travel sleep aid device of claim 85, wherein the longitudinal stiffening ribs are between about 0.8 inches to 0.9 inches in height at the midsection midpoint.
 90. The travel sleep aid device of claim 82, wherein the longitudinal stiffening ribs extend perpendicularly or nearly perpendicularly rearward from left and right sides of the back face of the rigid elongate lever member for maximum stiffening effectiveness.
 91. The travel sleep aid device of claim 85, wherein at their highest points corresponding to the midsection midpoint the stiffening ribs extend rearward and laterally from the back surface at an obtuse angle of at least 100 degrees relative to a horizontal stacking axis of the rigid elongate member, said horizontal stacking axis defined as a line drawn between lateral seating edges of a planar or curved front surface of the rigid elongate lever member, providing for stable, compact nested stacking of multiple elongate lever members for efficient storage and shipping without unacceptable loss of rigidity provided by the stiffening ribs.
 92. The travel sleep aid device of claim 91, wherein at their highest points the stiffening ribs extend rearward and laterally from the back surface at an obtuse angle of between 110 degrees and 120 degrees relative to the horizontal stacking axis of the rigid elongate member.
 93. The travel sleep aid device of claim 91, wherein at their highest points the stiffening ribs extend rearward and laterally from the back surface at an obtuse angle of between 105 degrees and 115 degrees relative to the horizontal stacking axis of the rigid elongate lever member.
 94. The travel sleep aid device of claim 91, wherein at their highest points the stiffening ribs extend rearward and laterally from the back surface at an obtuse angle of between 110 degrees and 115 degrees relative to the horizontal stacking axis of the rigid elongate member.
 95. The travel sleep aid device of claim 91, wherein at the top terminus of the upper lever arm the stiffening ribs extend rearward from the back surface at a perpendicular or nearly perpendicular angle of between about 90 degrees to 99 degrees relative to the horizontal stacking axis to afford substantial stiffening to adjust for the lesser height of the stiffening ribs at this portion of the lever member compared to the rib height at the midsection midpoint, and wherein a height of the stiffening ribs at the top terminus of the upper lever arm corresponds approximately to a separation distance between opposing surfaces of nested lever members at the midsection midpoint, whereby the stiffening ribs at the top terminus of one stacked lever member seat stably atop a corresponding back surface of a lower-stacked lever member to further secure multiple nested lever members in a compact, stable stacked array for improved storage and shipping.
 96. The travel sleep aid device of claim 95, wherein the height of the stiffening ribs at the top terminus of the upper lever arm and corresponding separation distance between opposing surfaces of nested lever members at the midsection midpoint are each within a range of between 0.10 inches and 0.30 inches.
 97. The travel sleep aid device of claim 95, wherein the height of the stiffening ribs at the top terminus of the upper lever arm and corresponding separation distance between opposing surfaces of nested lever members at the midsection midpoint are each within a range of about inches to 0.25 inches.
 98. A travel sleep aid device for stably and comfortably restraining a head position of an upright seated human user, comprising: A rigid elongate lever member sized and dimensioned for placement between a thoracic spinal region of a user's back and an upright seatback surface, the lever member having front and back surfaces, wherein a width dimension at a top terminus of the lever member is less than a width dimension at a bottom edge of the lever member; Head-bracing means attached to an upper, brace-anchoring segment of the rigid elongate lever member adapted to positionally secure a user's head relative thereto; and Longitudinal stiffening ribs extending rearward from right and left sides of the back surface of the rigid elongate lever member, the stiffening ribs highest at a middle region of the rigid elongate lever member and diminishing in height from the middle region in an angular or gradual curved height reduction profile toward the top and bottom edges where they are of substantially lesser height than at the middle region, or absent, wherein at their highest points corresponding to the lever member middle region the stiffening ribs extend rearward and laterally from the back surface at an obtuse angle of at least 100 degrees relative to a horizontal stacking axis of the rigid elongate member, said horizontal stacking axis defined as a line drawn between lateral seating edges of a planar or curved front surface of the rigid elongate lever member, whereby the stiffening ribs mediate stable, compact stacking of multiple elongate lever members for efficient storage and shipping without unacceptable loss of rigidity provided by the stiffening ribs.
 99. The travel sleep aid device of claim 98, wherein at their highest points the stiffening ribs extend rearward and laterally from the back surface at an obtuse angle of between 100 degrees and 120 degrees relative to the horizontal stacking axis of the rigid elongate member.
 100. The travel sleep aid device of claim 98, wherein at their highest points the stiffening ribs extend rearward and laterally from the back surface at an obtuse angle of between 105 degrees and 115 degrees relative to the horizontal stacking axis of the rigid elongate lever member.
 101. The travel sleep aid device of claim 98, wherein at their highest points the stiffening ribs extend rearward and laterally from the back surface at an obtuse angle of between 110 degrees and 115 degrees relative to the horizontal stacking axis of the rigid elongate member.
 102. The travel sleep aid device of claim 98, wherein at the top terminus of the lever member the stiffening ribs extend rearward from the back surface at a perpendicular or nearly perpendicular angle of between about 90 degrees to 99 degrees relative to the horizontal stacking axis to afford substantial stiffening to adjust for the lesser height of the stiffening ribs at this portion of the lever member compared to the rib height at the middle region, and wherein a height of the stiffening ribs at the top terminus of the lever member corresponds approximately to a separation distance between opposing surfaces of nested lever members at the middle region, whereby the stiffening ribs at the top terminus of one stacked lever member seat stably atop a corresponding back surface of a lower-stacked lever member to further secure multiple nested lever members in a compact, stable stacked array for improved storage and shipping.
 103. The travel sleep aid device of claim 95, wherein the height of the stiffening ribs at the top terminus of the upper lever arm and corresponding separation distance between opposing surfaces of nested lever members at the middle region are each within a range of between 0.10 inches and 0.30 inches.
 104. The travel sleep aid device of claim 95, wherein the height of the stiffening ribs at the top terminus of the upper lever arm and corresponding separation distance between opposing surfaces of nested lever members at the middle region are each within a range of about 0.15 inches to 0.25 inches.
 105. A method for restraining the head of a fatigued or sleeping person seated in an upright position to prevent involuntary forward and lateral flexion of the head, comprising: Positioning a rigid elongate lever member between a thoracic spinal region of the person's back and an upright seatback surface, the lever member having front and back surfaces and comprising upper and lower lever arms, wherein a width dimension of the upper lever arm is less than a width dimension of the lower lever arm, and wherein a midsection of the lever member defines an angular or arcuate longitudinal anatomical load displacement bend of the frontal surface between the upper and lower lever arms; Adjusting lower lever arm and fulcrum positions of the rigid elongate lever member in height relative to the user's thoracic spine to a comfortable, optimum force balancing position, wherein the longitudinal anatomical load displacement bend is positioned between the seat surface and a mid-thoracic portion of the person's back, and the lower lever arm is positioned between the seat surface and a mid-lower-thoracic portion of the person's back; and Engaging head-bracing means attached to the upper lever arm to positionally secure the person's head relative to the upper lever arm, whereby rearward forces against the upper lever arm are transmitted through the head-bracing means to oppose frontal flexion loads of the user's head when neck muscles are relaxed during fatigue or sleep.
 106. The method of claim 105, wherein the longitudinal anatomical load displacement bend is positioned between the seat surface and an optimal anatomical fulcrum position spanning or disposed between the person's fourth-seventh thoracic vertebrae.
 107. The method of claim 105, wherein the longitudinal anatomical load displacement bend is positioned between the seat surface and an optimal anatomical fulcrum position spanning or disposed between the person's fifth-sixth thoracic vertebrae.
 108. The method of claim 105, wherein the longitudinal anatomical load displacement bend is positioned between the seat surface and an optimal anatomical fulcrum position disposed between the person's fifth-sixth thoracic vertebrae.
 109. The method of claim 105, wherein the rigid elongate lever member makes contact with the person's back spanning positions of at least fifth through ninth thoracic vertebrae.
 110. The method of claim 105, wherein contact between the rigid elongate lever member is restricted to between the person's back between the third and eleventh thoracic vertebrae.
 111. A travel sleep aid device for stably and comfortably restraining a head position of an upright seated human user, comprising: A rigid elongate lever member sized and dimensioned for placement between a thoracic spinal region of a user's back and an upright seatback surface, the lever member having front and back surfaces and comprising upper and lower lever arms, wherein a width dimension of the upper lever arm is substantially the same as a width dimension of the lower lever arm, and wherein a midsection of the lever member defines an angular or arcuate longitudinal anatomical load displacement bend of the frontal surface between the upper and lower lever arms; and Head-bracing means attached to the upper lever arm adapted to positionally secure a user's head relative to the upper lever arm, whereby rearward forces against the upper lever arm are transmitted through the head-bracing means to oppose frontal flexion loads of the user's head.
 112. The travel sleep aid device of claim 111, wherein the longitudinal anatomical load displacement bend comprises at least a 5-degree angle or curve of the frontal surface between the upper and lower lever arms, whereby a frontal longitudinal axis of the upper lever arm diverges frontally at least 5 degrees from a frontal longitudinal axis of the lower lever arm.
 113. The travel sleep aid device of claim 111, wherein the longitudinal anatomical load displacement bend comprises an angle or curve of the inner surface no greater than 30 degrees between an upper end of the upper lever arm and a lower end of the lower lever arm, whereby a frontal longitudinal axis of the upper lever arm diverges frontally no more than 30 degrees from a frontal longitudinal axis of the lower lever arm.
 114. The travel sleep aid device of claim 111, wherein the longitudinal anatomical load displacement bend comprises an angle or curve of the inner surface within a range of 10-20 degrees between an upper end of the upper lever arm and a lower end of the lower lever arm, whereby a frontal longitudinal axis of the upper lever arm diverges frontally within a range of 10-20 degrees from a frontal longitudinal axis of the lower lever arm. The travel sleep aid device of claim 75, having multiple longitudinal stiffening ribs extending from at least a portion of the back face of the rigid elongate lever member.
 115. The travel sleep aid device of claim 111, having longitudinal stiffening ribs extending from left and right sides of the back face of the rigid elongate lever member, at least throughout a midsection of the rigid elongate lever member corresponding to a longitudinal span of the anatomical load displacement bend.
 116. The travel sleep aid device of claim 115, having longitudinal stiffening ribs extending rearward from left and right sides of the back face of the rigid elongate lever member. 